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  1. #include <iostream>
  2. #include <thread>
  3. #include <vector>
  4. #include <algorithm>
  5. #include <mutex>
  6. #include <chrono>
  7.  
  8. using namespace std;
  9.  
  10.  
  11. struct Data
  12. {
  13.   mutex lock;
  14.   vector<char> v;
  15.   char current = 'A';
  16.  
  17. } data;  
  18.  
  19. char next(char ch)
  20. {
  21.    switch(ch)	
  22.    {
  23.    	 case 'A': return 'B';
  24.    	 case 'B': return 'C';
  25.    	 case 'C': return 'A';
  26.    }
  27. }
  28.  
  29. void threadSafeOrderedPrint(char ch)
  30. {
  31. 	lock_guard<mutex> l(data.lock);
  32. 	data.v.push_back(ch);
  33. 	while(!data.v.empty())
  34. 	{
  35. 	   	auto it = find(begin(data.v),end(data.v),data.current);
  36. 	   	if(it==end(data.v))
  37. 	   	  return;
  38.  
  39. 	    cout<< *it;
  40. 	    data.current = next(data.current);
  41. 	    data.v.erase(it);
  42. 	}
  43. }
  44.  
  45.  
  46. void foo(const char ch)
  47. {
  48.     for (int i=0; i<25; ++i) 
  49.     {
  50.        this_thread::sleep_for(chrono::milliseconds(10));
  51.        threadSafeOrderedPrint(ch);
  52.     }
  53. }
  54.  
  55. int main()
  56. {
  57.     vector<thread> threads;
  58.     threads.reserve(3);
  59.     threads.emplace_back(foo, 'A');
  60.     threads.emplace_back(foo, 'B');
  61.     threads.emplace_back(foo, 'C');
  62.  
  63.     for(auto & t : threads) 
  64.         t.join();
  65.  
  66.     cout<<endl<<"Finished"<<endl;    
  67.  
  68.     return 0;
  69. }
Success #stdin #stdout 0s 4528KB
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stdin
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Standard input is empty
stdout
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ABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABCABC
Finished
https://ideone.com/5W56J2
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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